Bunuel wrote:
If x is an integer, then is x a prime number?
(1) x is a multiple of a prime number --> if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.
(2) x is a product of two integers --> the same here: if x=1*2=2 then the asnwer is Yes, but if x=1*4=4 then the answer is NO. Not sufficient.
(1)+(2) The same xample: if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.
Answer: E.
let me just further elaborate on Bunuel
(1) let the prime number be 2 then 2*1= 2 this is a prime number
again 2*2 =4 this is not a prime number so both 2 and 4 are multiples of the prime number 2, but 2 is a prime number and 4 is not so (1) is not sufficient
similarly 6 is a product of 2 integers 3*2 and 6 is not a prime number
but 2 is also a multiple of 2 integers 1*2 and 2 is a prime number
so (2) is also not sufficient
Taking both (1) and (2)
First number 2 , (1) Is a multiple of a prime no.( 2*1)
(2) is the product of 2 integers (2*1)
and 2 is a prime number
second number 6, (1) Is a multiple of a prime no.( 3*2)
(2) is the product of 2 integers (3*2)
and 6 is not a prime number
as both 1 and 2 together do not give a consistent answer the answer is e
Hope I have understood it correctly ,
Thanks Bunuel